Degradation of Metronidazole from Aqueous Environment Using Hydrothermally Synthesized ZnO, N-Doped ZnO, and ZnO/AC Nanoparticles

Abstract

ZnO, ZnO (calcined at 400°C), nitrogen-doped ZnO nanoparticles, and activated carbon (AC) impregnated with ZnO (ZnO/AC) nanocomposites were synthesized by the hydrothermal method. The structural, morphological, and optical properties of the synthesized complexes were studied by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformation infrared analysis (FTIR), Brunauer−Emmett−Teller (BET) analysis, and UV-visible spectroscopy analysis. The degradation of the antibiotic metronidazole (MNZ) from aqueous solutions was examined by the photocatalytic process of those synthesized complexes. Among the four complexes, ZnO/AC was confirmed to be a capable prospective both as an efficient photocatalyst and as an adsorbent. The optimal photodegradation condition obtained was 0.9 g/L and pH = 9. After 300 minutes, 99% of MNZ was removed by ZnO/AC. Finally, gas chromatography-mass spectroscopy was conducted to identify the degradation intermediates.